Many types of insecticides have been used to kill mosquitoes and other insect pests. Nevertheless, many insecticides have disadvantages. Some insecticides are toxic to humans, are harmful to the environment, or have limited efficacy. Further, there is an increasing demand for compositions containing naturally occurring or so-called organic compounds. Accordingly, there is a continuing need for organic compounds having improved insecticidal properties, while being substantially non-toxic or only mildly toxic to humans.
Certain plant species produce essential oils that serve as natural sources of insect repellents, insecticides, fragrances, or other useful chemicals. For example, perilla oil and certain of its components have been used in a variety of applications, including in varnishes, in the production of inks and linoleums, and in the culinary field as a marinade.
Perilla oil is extracted from annual herbs belonging to the genus Perilla through several methods, including but not limited to cold pressing of the seeds or steam distillation of the leaves. Two types of perilla oil are available, seed and leaf extracts. The major component of perilla seed extract is linolenic acid, and the major components of perilla leaf extract are perillaldehyde, limonene, β-caryophyllene, and farnesene.